Climatology
Climatology is the science or branch of geography and Earth sciences that deals with the study of meteorological phenomena and their variations over chronological time. It has been a matter that geography has dealt with since its inception: Claudius Ptolemy, in his book Geographia, devotes a third of it to the zonal variation of climates on the earth's surface.
Although it uses the same parameters as meteorology (the science that studies the weather), its objective is different, since it does not intend to make immediate forecasts, but to study long-term climatic characteristics.
Many human activities depend on the weather conditions, from agriculture to a simple walk in the countryside. That is why an enormous effort has been made to predict the weather in both the short and medium term.
When a region, city, hillside, etc. it has a differentiated climate from the zonal climate, it is said to be a 'topoclimate'; This is characterized by being mostly affected by the local state of the rest of the geographical factors (geomorphology, hydrography, etc.). In addition, a microclimate is one that does not have lower divisions, such as the one in a room, under a tree or on a certain street corner. It fundamentally determines the main characteristics of bioclimatic architecture.
The climate tends to be regular in very long periods, even geological, largely determining the evolution of the geographical cycle of a region, which allows the development of certain vegetation and a type of soil determined by latitude, that is that is, zonal soils. But, in geological periods, the climate also changes naturally, the types of weather change and there is a change from one climate to another in the same area.
Weather and climate take place in the atmosphere. To define a climate, observation over a long period is necessary (the World Meteorological Organization established minimum periods of thirty years, but there are authors who believe that they should be longer, one hundred or more, to record variations sufficiently). The observations of temperature, atmospheric pressure, winds, humidity and precipitation, as well as the type or types of weather that are collected in the meteorological stations. With these data tables of average values are prepared that are transferred to climograms, graphic representations of the annual variation of temperature and precipitation, as variables.
History
The Greeks began the formal study of climate; in fact, the word climate derives from the Greek word klima, which means "slope", referring to the slope or tilt of the Earths axis. Arguably the most influential classical text on climate was On Air, Water, and Places written by Hippocrates around 400 BCE. This work discussed the effect of climate on human health and cultural differences between Asia and Europe. This idea that climate controls which countries excel based on their climate, or climate determinism, continued to be influential throughout history. Chinese scientist Shen Kuo (1031-1095) deduced that climates changed naturally over an enormous span of time, after observing petrified bamboo found underground near Yanzhou (present-day Yanzhou). #39;an, Shaanxi Province), an area with a dry climate unsuitable for the growth of bamboo.
The invention of the thermometer and barometer during the Scientific Revolution enabled systematic recording, which began as early as 1640-1642 in England. Early climate researchers included Edmund Halley, who published a map of the trade winds in 1686 after a trip to the southern hemisphere. Benjamin Franklin (1706-1790) first charted the course of the Gulf Stream for use in sending mail from the United States to Europe. Francis Galton (1822-1911) invented the term anticyclone. Helmut Landsberg (1906-1985) encouraged the use of statistical analysis in climatology, which led to its evolution into a physical science.
In the early 20th century, climatology focused primarily on describing regional climates. This descriptive climatology was primarily an applied science, providing farmers and other interested persons with statistics about what was normal weather and how likely extreme events were to occur. To do this, climatologists had to define a normality. weather, or an average of weather and climate extremes over a period that is typically 30 years.
By the middle of the 20th century, many assumptions in meteorology and climatology considered climate to be more or less constant. Although scientists were aware of past climate changes, such as the ice age, the concept of unchanging climate was useful for developing a general theory of what determines climate. This began to change in the following decades, and although the history of climate change science began earlier, climate change did not become one of the most important topics of study for climatologists until the 1970s.
Methods
The study of contemporary climates incorporates meteorological data accumulated over many years, such as precipitation records, temperature, and atmospheric composition. Knowledge of the atmosphere and its dynamics is also captured in models, either statistical or mathematical, which help to integrate different observations and see how they fit together. Modeling is used to understand past, present and future climates.
Climate research is hampered by the large scale, long time periods, and complex processes that govern it. The weather is governed by physical laws that can be expressed as differential equations. These equations are coupled and not linear, so approximate solutions are obtained using numerical methods to create global climate models. Climate is sometimes modeled as a stochastic process, but this is generally accepted as an approximation to processes that are otherwise too complicated to analyze.
Climate data
The collection of long-term records of climate variables is essential for the study of climate. Climatology deals with the aggregate data that meteorology has collected. Scientists use direct and indirect observations of the climate, from Earth-observing satellites and scientific instrumentation such as a global network of thermometers, to prehistoric ice mined from glaciers. As measurement technology changes over time, data records cannot be directly compared. As cities tend to be warmer than their surrounding areas, urbanization has made it necessary to constantly correct the data for this urban heat island effect.
Models
Climate models use quantitative methods to simulate the interactions of the atmosphere, oceans, land surface, and ice. They are used for various purposes, from studying the dynamics of the weather and climate system to projections of future climate. All climate models balance, or nearly so, incoming energy in the form of shortwave (including visible) electromagnetic radiation toward Earth with outgoing energy in the form of longwave (infrared) electromagnetic radiation from Earth. Any imbalance causes a change in the Earth's average temperature. Most climate models include the radiative effects of greenhouse gases, such as carbon dioxide. These models predict an upward trend in surface temperatures, as well as a more rapid increase in temperature at higher latitudes.
Models can range from relatively simple to complex:
- A simple radiant heat transfer model that treats the earth as a single point and averages the outgoing energy.
- This can be expanded vertically (radio-conviction models), or horizontally
- Model coupled atmosphere-ocean-sea ice. General circulation models differ and resolve the complete equations of mass transfer and energy and radiant exchange.
- Earth system models also include the biosphere.
In addition, they are available in different resolutions ranging from >100km to 1km. The high resolutions of global climate models are very computationally demanding and only a few global data sets exist. Some examples are ICON or technically reduced data such as CHELSA (High Resolution Climatologies for Land Surface Areas).
Research topics
The topics that climatologists study fall broadly into three categories: climate variability, mechanisms of climate change, and modern climate change.
Climatological processes
Several factors influence the average state of the atmosphere at a given location. For example, mid-latitudes will have pronounced seasonality in temperature while tropical latitudes show little variation in temperature throughout the year. Another important control on climate is continentality: distance from large bodies of water such as oceans.. The oceans act as a moderating factor, so the lands near them tend to have mild winters and mild summers. The atmosphere interacts with other spheres of the climate system, with winds generating ocean currents that carry heat around the planet.
Climate classification
Classification is an important aspect of many sciences as a tool to simplify complicated processes. Throughout the centuries different climatic classifications have been developed, the first being in Ancient Greece. The way to classify climates depends on your application. A wind power producer will require different information (wind) in the classification than someone interested in agriculture, for whom precipitation and temperature are more important. The most widely used classification, the Köppen climate classification, was developed at the turn of the century. XIX and is based on vegetation. Uses monthly temperature and precipitation data.
Climate variability
There are different modes of variability: recurring patterns of temperature or other climatic variables. They are quantified with different indices. In the same way that the Dow Jones Industrial Average, based on the stock prices of 30 companies, is used to represent fluctuations in the stock market as a whole, weather indices are used to represent the essentials of weather. Climate indices are often designed with the twin goals of simplicity and completeness, with each index typically representing the location and timing of the climate factor it represents. By their very nature, indices are straightforward, combining many details into a general description of the atmosphere or ocean that can be used to characterize factors influencing the global climate system.
The El Niño-Southern Oscillation (ENSO) is a coupled ocean-atmosphere phenomenon in the Pacific Ocean responsible for most of the global temperature variability, and has a cycle of between two and seven years. The North Atlantic Oscillation is a mode of variability that is confined primarily to the lower atmosphere, the troposphere. The layer of the upper atmosphere, the stratosphere, is also capable of creating its own variability, most notably in the Madden-Julian Oscillation (MJO), which has a cycle of approximately 30-60 days. The Pacific Interdecadal Oscillation can create changes in the Pacific Ocean and lower atmosphere on decadal time scales.
Climate change
Climate change occurs when changes in Earth's climate system result in new weather patterns that persist over a long period of time. This period of time can be as short as a few decades or as long as millions of years. The climate system receives almost all of its energy from the sun. The climate system also emits energy into outer space. The balance between incoming and outgoing energy, and the passage of energy through the climate system, determines the Earth's energy budget. When the incoming energy is greater than the outgoing, the Earth's energy balance is positive and the climate system warms up. If more energy comes out, the energy balance is negative and the Earth cools down. Climate change also influences the mean sea level.]
Modern climate change is driven by human greenhouse gas emissions from the burning of fossil fuels that increase the global average surface temperature. However, rising temperatures are only one aspect of modern climate change, as changes in precipitation, storm tracks, and cloudiness have also been observed. Warmer temperatures are driving other changes in the climate system, such as widespread melting of glaciers, rising sea levels, and changes in flora and fauna.
Differences with the weather
Unlike meteorology, which focuses on short-term weather systems that last up to a few weeks, climatology studies the frequency and trends of those systems. It studies the periodicity of weather phenomena over the years to millennia, as well as changes in long-term average weather patterns, in relation to atmospheric conditions. Climatologists study both the nature of climates—local, regional, or global—and the natural or human-induced factors that cause climates to change. Climatology takes into account the past and can help predict future climate change.
Phenomena of climatological interest include the atmospheric boundary layer, circulation patterns, heat transfer (radiative, convective, and latent), atmosphere-ocean interactions, and land surface (particularly vegetation, land use and topography), and the chemical and physical composition of the atmosphere.